Our aim is to gain understanding of human language through further investigation of a village sign language, created within the past 75 years with little if any outside influence. When a small group of people grow up together with no direct linguistic input, the language that they create should provide a window into the fundamentals of all human languages. The object of study is Al-Sayyid Bedouin Sign Language (ABSL), named after the community in the south of Israel where the language was created. The language is used by deaf and hearing people, and is the second language of the village after the local dialect of Arabic. The language of the older signers, which serves a wide range of communicative functions, is highly regular in some ways. However, unlike more mature sign languages, it appears to be remarkably spare in grammatical structure, suggesting that functional human language is possible without complex grammar. The language of younger signers shows indications of more complexity and regularity, and it is to this group that we propose to turn our attention. We are particularly interested in the development of the following types of linguistic complexity: syntactic embedding, dual patterning, complex word formation, and prosodic structure. More fundamentally, we are interested in uncovering the mechanisms and social circumstances that permit the development of more complex language from the simple systems found among older signers of ABSL. Using a variety of elicitation tools that we developed for this language and community, we will videotape signers of three generations on tasks designed to produce (a) complex sentences;(b) citation forms of vocabulary items;(c) compound words;and (d) descriptive narratives. Propositional complexity such as embedding is signaled by prosody in ABSL, and we will use a specially created, detailed prosodic coding system to identify the development of complexity across age groups. The requirement for duality of patterning in human language -- a meaningless level of formational elements that combine to form the meaningful words and sentences of language -- has never been challenged before, and we will investigate this issue from three main angles: (1) phonological analysis across generations and in comparison with a mature sign language, (2) a perception experiment designed to tease apart gradient from discrete identification of handshapes, and (3) a laboratory evolution experiment attempting to identify the self-organization of duality from holistic forms through iterated social transmission. A sign language density profile will be recorded for all signers to reveal the amount of sing language interaction in their families and cohorts, as a means of mapping the innovation and spread of linguistic regularity and complexity in the community. We expect this rare opportunity to document a new language and the emergence of conventionalization and complexity to provide a model of the essential elements of language and their organization, forming the basis for any intervention program where normal access to or production of language is hampered. PUBLIC HEALTH RELEVANCE: We expect this rare opportunity to document a new language and the emergence of conventionalization and complexity to be highly relevant for all language related health issues. It will provide a model of the essential elements of natural language and their organization, forming a basis for any intervention program where normal access to or production of language is hampered, e.g., for SLI;young deaf children in need of a basis for proficiency in sign, oral, or written language;autism;cerebral palsy or other conditions requiring symbol manipulation communication systems;etc.